1. Technical Field
The present invention relates to an oscillator, an electronic apparatus, and a moving object.
2. Related Art
A temperature compensated crystal oscillator (TCXO) includes a crystal resonator and an integrated circuit (IC) for oscillating the crystal resonator, and can obtain high frequency accuracy, as the IC compensates (temperature-compensates) for deviation (frequency deviation) from a desired frequency (nominal frequency) of an oscillation frequency of a crystal resonator at a predetermined temperature range. An AT cut resonator is used as a resonator of the TCXO. Since the AT cut resonator exhibits frequency temperature characteristics of a third order curved line, the AT cut resonator has an advantage in which a stable frequency is obtained at a wide temperature range, compared to other cut resonators. Recently, an AT cut resonator has been miniaturized by applying a lithography technology to processing of quartz crystal. An AT cut resonator is disclosed in, for example, JP-A-2005-094410. A TCXO is disclosed in, for example, JP-A-2013-243481.
However, since frequency variable sensitivity (element sensitivity) of an AT cut resonator decreases according to miniaturization of the AT cut resonator, it is necessary to widen a variable range of a voltage (temperature compensation voltage) which is applied to a variable capacitance element by an IC, in order to realize a greater frequency variable width than a width of frequency deviation of the AT cut resonator at a predetermined temperature range, for example. By doing so, a temperature compensation voltage that exceeds a voltage range in which a capacitance value approximately linearly changes is applied to a variable capacitance element, temperature compensation accuracy is degraded, an output frequency of a temperature compensated oscillator changes depending on temperature, and thus, there is a problem that frequency deviation increases.